Calculating uncertainty in a experiment

[bobred]

Homework Statement

Finding uncertainty in magnetic field strength. N=2, i=1.00\pm0.005 A, R=0.1 m, \tan \theta=0.49\pm0.008

Homework Equations

The equation

B_{coil}=\frac{\mu_0 N i}{2 R \tan \theta}

The Attempt at a Solution

I am assuming that the radius R and number of turns N are exact.
I know how to find the error when the equation is X=a/b
Should I find this error and scale it by
\frac{\mu_0 N}{2 R}?

 

[mathfeel]

For multivariable formula y = f(x_1, x_2, \dots, x_n): \Delta y^2 = \sqrt{\sum_{j=1}^{n} \left( \frac{\partial f}{\partial x_j} \Delta x_j \right)^2}

It looks tedious, but try to work out and simplify the algebra before you plug in number.

 

[PeterO]

Homework Statement

Finding uncertainty in magnetic field strength. N=2, i=1.00\pm0.005 A, R=0.1 m, \tan \theta=0.49\pm0.008

Homework Equations

The equation

B_{coil}=\frac{\mu_0 N i}{2 R \tan \theta}

The Attempt at a Solution

I am assuming that the radius R and number of turns N are exact.
I know how to find the error when the equation is X=a/b
Should I find this error and scale it by
\frac{\mu_0 N}{2 R}?

Your proposal sounds fine to me.

 

[bobred]

Hi

Sorted it out, my problem, I mis-read the formula

\frac{\delta X}{X}=\sqrt{(\frac{\delta A}{A})^2+(\frac{\delta B}{B})^2}

For \delta X I needed to have

\delta X=\sqrt{(\frac{\delta A}{A})^2+(\frac{\delta B}{B})^2} X

Silly mistake
Thanks